Lactoferrin is a single chain metal-binding glycoprotein with a molecular weight of 77 kd. It has been found that the structural domain of lactoferrin responsible for the bactericidal properties is a pepsin-cleaved fragment called lactoferricin (see e.g. Bellamy W., et al., Identification of the bactericidal domain of lactoferrin, Biochim. Biophys. Acta 1121: 130-136, 1992, and Bellamy W., et al., Antibacterial spectrum of lactoferricin B, a potent bactericidal peptide derived from the N-terminal region of bovine lactoferrin, J. Appl. Bact. 73: 472-479, 1992).
Lactoferrin receptors are found on many types of cells including monocytes and macrophages, lectin-stimulated human peripheral blood lymphocytes, brushborder cells, and tumour cell lines.
Several patent publications describe the possible use of lactoferrin for treatment of infections or inflammations. In WO 98/06425, e.g., it is disclosed that lactoferrin and lactoferricin can be used for treatment and prevention of infections, inflammations and tumours.
EP 629 347 describes an antimicrobial agent containing (A) lactoferrin hydrolysate and/or one or more of antimicrobial peptides derived from lactoferrins, and (B) one or more compounds selected from the group consisting of metal-chelating protein, tocopherol, cyclodextrin, glycerine-fatty acid ester, alcohol, EDTA or a salt thereof, ascorbic acid or a salt thereof, citric acid or a salt thereof, polyphosphoric acid or a salt thereof, chitosan, cysteine, and cholic acid as the effective components thereof. This antimicrobial agent is intended for treatment of products, and especially for safely treating e.g. food and medicines. The agent according to this publication is thus a new preservative. In the publication several peptide sequences are given and some of them resemble the peptides according to the invention, although there are several important differences described further below.
U.S. Pat. No. 5,304,633 discloses antimicrobial peptides isolated from hydrolysates of human and bovine lactoferrin. Isolation of peptides corresponding to amino acids 12 to 47, and 17 to 41 of human lactoferrin are specifically disclosed.
JP 7145196 describes the preparation of antibiotic peptides by hydrolysis of lactoferrin. The preparation of a peptide corresponding to amino acids 17 to 41 of human lactoferrin is specifically described.
JP 8040925 discloses pharmaceutical compositions containing lactoferrin derived peptides and their use in the treatment of cornea damages, especially keratitis. Peptides corresponding to amino acids 17 to 41, 12 to 58, and 19 to 38, of human lactoferrin are specifically disclosed.
JP 7274970 describes the recombinant production of antibacterial lactoferricin derived peptides, specifically a peptides corresponding to amino acids 18 to 42 of human lactoferrin is disclosed.
JP 8143468 describes lactoferrin derived peptides and their use as antiulcer drugs, a peptide corresponding to amino acids 19 to 33 of human lactoferrin is specifically disclosed.
WO 00/01730 describes peptides derived from human lactoferrin and their use for treatment of infections and inflammations.
EP 1 228 097 describes peptides derived from the immediate N-terminal end of human lactoferrin and their use as microbial agents.
EP 1151009 describes peptides comprising a sequence corresponding to amino acids 35 to 50 of human lactoferrin having antimicrobial and/or endotoxin neutralizing activity.
WO 2006/047744 describes immunomodulatory peptides derived from the N-terminal part of human lactoferrin comprising at least 33 amino acids and being substituted in both the N- and C-terminus with four positively charged amino acids.